1. Technical Field
The present disclosure relates to lens modules, and particularly to a lens module that is capable of performing infrared and visible-spectrum photography.
2. Description of Related Art
Nowadays, camera modules are in widespread use. Camera modules are combined with various portable electronic devices such as mobile phones, personal digital assistants (PDAs) and other handheld computers so that the portable electronic devices are more multi-functional.
A typical camera module generally includes a lens module. The lens module is one of the major components of the camera module. The lens module is coupled with an image sensor such as a charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) to capture images. Generally speaking, the image sensor reacts to light both in the visible spectrum and in the infrared spectrum. Light in the infrared spectrum can cause the image sensor's signal-to-noise ratio to be reduced when the lens module is used in natural light conditions for visible-spectrum photography. Therefore, an infrared-cut filter that blocks light in the infrared spectrum is fitted in the lens module to prevent such problem.
However, the lens module having an infrared-cut filter is only capable of performing visible-spectrum photography. Thus the functionality of the lens module is restricted to some extent. For example, such a lens module cannot ideally be used in dark environments for photography because of the lack of visible-spectrum light. Although infrared light is emitted by all objects all the time, even in dark environments, the lens module cannot be used for infrared photography due to infrared light being blocked by the infrared-cut filter.
What is needed, therefore, is a lens module that is capable of performing both infrared and visible-spectrum photography.
A lens module includes a barrel receiving a lens system therein, an infrared-cut filter, an infrared-pass filter, and a switching mechanism. The switching mechanism includes a connecting member interconnecting the infrared-cut filter and the infrared-pass filter, a first magnetic member fixed at the barrel, and a second magnetic member fixed at the connecting member. The first and second magnetic members are configured for driving the connecting member to move relative to the barrel so as to selectively bring either the infrared-cut filter or the infrared-pass filter into optical alignment with the lens system in the barrel.
Other advantages and novel features of the present invention will become more apparent from the following detailed description of embodiments when taken in conjunction with the accompanying drawings.